Uhm, if i'm incorrect about this, I apologize. Seems like you haven't gotten the answer you work looking for. Apologies for the wordy reply.

I believe, there are a few ways to solve this...
A.1) you can armature the broom, as well as the hand
2)Build a bone for the broom, and build a bone for the Hand
3)Parent the broom's bone TO the hand, (they can be constructed in the same armature, just set the bones up so they do not have to be connected. And make sure you label them to minimize confusion).
3.i) You also want to have 'inherit location' enabled.
4) You can have multiple object share the same armature. Once set-up apply the modifier tool to both objects. (Object 1 = hand, Object 2 = broom/item)

I think you should be good from there... The broom should be able to move separately from the hand, and you can always toggle on and off the parenting. And tinker around with the idea.

Honestly, i think animating is a little too complex (for me). There are a lot of ways you can probably pull this off. But that would most likely be my take on the whole project. You could probably find something else that works for you. But if anything i recommend an animation tutorial, one associated with 'gaming'. You may get more out of it. Like toggling visibility, or having it appear when and where you need it to, and so on...

But hey, if you have any trouble... (Sorry, i only left you with one example, i'm not too big on animating).